This invention relates to an improved driveway sealer tar and more specifically to a tar used as a raw material in the manufacture of driveway sealer emulsion. The improved tar, the subject of the instant invention, is prepared by oxidizing a selected coal tar distillation cut and is characterized by being relatively less brittle in cold weather and having significantly less odor as compared to commercially available tars.
Bituminous pavement sealers of two main types are used in roadway or driveway surfacing; those produced from asphaltic petroleums and those from coal tars. Typically, a bituminous pavement sealer is composed of water, clay and bitumen in the form of an emulsion. Other formulations are possible. Sealers produced from asphaltic bitumens tend to dissolve in petroleum oils and greases and, thus, surfaces composed of such bitumens suffer serious damage when exposed to such petroleum products, as for example, to jet fuel, gasoline or motor oil and the like.
Also used as sealers for bituminous pavements are emulsions manufactured from coal tars. These coal tars are obtained in the distillation of crude tars resulting from the destructive distillation of bituminous coal, the principal source of such tar being the by-product of coke ovens producing metallurgical coke. While coal tar derived compositions have superior wetting characteristics and are resistant to both water and petroleum oils and greases, they suffer from the disadvantage of having an unpleasant odor, becoming brittle at low temperatures or tending to soften excessively at higher temperatures. Characteristics of this kind are a drawback in sealer applications where the aim is to protect the paved surface contiguous to residences or business buildings.
Accordingly, a need exists for an improved bitumen for use in sealer manufacture. The use of the improved bitumen produced in accordance with the invention will result in a sealer which is less brittle in cold weather and which is characterized as having significantly less odor.